What's this, a drabble? Came to me on the train. Initially I wanted to do this with 100 characters, and not 100 words, but then I wasn't sure if spaces counted and so I just did the lazy thing and wrote it as a drabble instead.
When you left, I planted a tree. I would sit under it every day, and cry. My tears watered it. I thought of Cinderella, and the spirit of her mother. Maybe the spirit of our love would come back to me some day, if I tended faithfully to its remains. I promised I would never forget, never listen to the friends who told me to just get over it.
But trees need a lot of water, and a girl can only cry so much.
I met him before it had grown stout. And it withered, and died. I’m not sorry.
And the 100-characters (counting spaces and punctuation) version:
I planted a tree when you left. My tears watered it. But it was thirsty, and I can only cry so much.
The other idea I had on the train, this one does work with 100 characters, counting spaces:
His most serene highness, the emperor Ferdinand Archibald Van Hooferschteinen III, slept peacefully.